Hair straightener



FIG. 1 is a front, right side, top perspective view of a hair straightener showing my new design;

FIG. 2 is a rear, left side, bottom perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is a front, right side, top perspective view thereof in an open position of use.

The broken lines depict portions of the hair straightener that form no part of the claimed design. 

CLAIM The ornamental design for a hair straightener, as shown an described. 